Various bar code symbols are widely used to label items for product identification or other purposes. Generally speaking, a bar code symbol consists of a sequence of light and dark regions referred to as elements or bars. These elements are typically rectangular in shape and often have a variety of possible widths. An arrangement of elements represents a character and is determined according to a set of rules and definitions typically referred to as a "code". A variety of codes such as the Universal Product Code (UPC) and Code 39 exist and provide a degree of conformity.
More specifically, codes define a set of characters wherein each character is depicted and defined by a unique arrangement of elements. To encode a desired message having a number of characters, a collection of arrangements of elements are concatenated to form a bar code symbol. Each character of the message is represented by its own corresponding group of elements.
In the field of photography, it is known for a rotatable film spool to include a coaxial disk having a bar code symbol which consists of a sequence of white and black bars or elements. For example, see commonly assigned U.S. Pat. No. 5,023,642, issued Jun. 11, 1991, No. 5,030,978, issued Jul. 9, 1991, and No. 5,032,854, issued Jul. 16, 1991. The black bars are printed in spaced relation on an otherwise white bar code label that is adhered to the spool disk. The bar code symbol that results is used to provide film-related information, such as film speed (ISO), film type, total number of film exposures available, etc..